Electric Field Effects with Alcohol Dehydrogenase

Abstract

Extending previous work with electrostimulation of yeast dehydrogenases in cell suspension, we attempted to influence the alcohol dehydrogenase system in vitro using methylene blue as the acceptor. According to the conformational coupling model and the free radical hypothesis, the possibility of capacitive current treatment was tested by short applications of E = 10, 20, and 30 V/cm at a frequency of 50 Hz. Besides a temperature rise, no significant kinetic data from spectrophotometry or polarography could be measured, nor could inductive coupling using magnetic fluxes of 1, 5, and 10 mT. On the other hand, marked changes of relative electrofusion yield were found after interaction of dehydrogenases with membrane surfaces of barley protoplasts. It was confirmed that in unbuffered solution containing 0.5 M mannitol, the isoelectric point (PI) of enzymes determines the relative fusion yield: Fr < 1 for pI < 7 and Fr > 1 for pI > 7. We must conclude that only the position of dehydrogenases at or within cell membranes shows responses to weak ac or stronger dc treatments influencing additionally electric moments and conformations by surface potential and adsorption energy.

Key Words:

• Alcohol dehydrogenase
• Electrostimulation in vitro
• Enzyme adsorption
• Modification of electrofusion
• Isoelectric point
• ECC model
• MCI model